I have installed OpenCv on my Raspberry pi Model 3B. It is working for python 2.7 but not for python 3
The error im getting is:

pi@raspberrypi:~ $ python3
Python 3.7.3 (default, Dec 20 2019, 18:57:59)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.

import cv2
Traceback (most recent call last):
File "", line 1, in
File "/home/pi/.local/lib/python3.7/site-packages/cv2/init.py", line 3, in < module>
from .cv2 import *
ImportError: /home/pi/.local/lib/python3.7/site-packages/cv2/cv2.cpython-37m-arm-l inux-gnueabihf.so: undefined symbol: __atomic_fetch_add_8

I tried using cmake: according to https://answers.opencv.org/question/215735/make-error-__atomic_fetch_add_8-on-raspberrypi4/

I am getting the followin error:
pi@raspberrypi:~ $ cmake -DCMAKE_BUILD_TYPE=Release \

-D OPENCV_EXTRA_MODULES_PATH=${HOME}/opencv_contrib-${OPENCV_VERSION}/m odules \
CMake Warning:
No source or binary directory provided. Both will be assumed to be the same as the current working directory, but note that this warning will become a fatal error in future CMake releases.

CMake Error: The source directory "/home/pi" does not appear to contain C MakeLists.txt.


installed opencv-python= and it worked using pip install opencv-python=

1 Answer 1


(Updated 12 Oct 2020)

There's a known issue with some old opencv wheels on piwheels. You need to preload python3 with:

LD_PRELOAD=/usr/lib/arm-linux-gnueabihf/libatomic.so.1 python3

But newer versions are now available: https://www.piwheels.org/project/opencv-python/

  • tried it i am getting bash command not found error
    – apurva_b
    Feb 28, 2020 at 12:27

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